Thousands of documents in his possession include the 'instruction manual' for how NSA is built.
According to journalist Glenn Greenwald, NSA whistleblower Edward Snowden has the equivalent of "blueprints" for the NSA in his possession. But you won't be seeing them any time soon.
In an interview with the Associated Press, Greenwald said that Snowden has “basically the instruction manual for how the NSA is built" in the thousands of documents he snagged before fleeing his job at NSA contractor Booz Allen, and then, American soil. He's now holed up in a Moscow airport as journalists continue to chase down planes he's not on.
Apparently, Snowden doesn't want the information in those documents to become public. Here's Greenwald, speaking for Snowden, on why that is, and why he grabbed the information in the first place:
“In order to take documents with him that proved that what he was saying was true he had to take ones that included very sensitive, detailed blueprints of how the NSA does what they do...“I think it would be harmful to the U.S. government, as they perceive their own interests, if the details of those programs were revealed."